From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-182.mta1.migadu.com (out-182.mta1.migadu.com [95.215.58.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 50C061FE44B for ; Tue, 16 Sep 2025 15:52:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758037954; cv=none; b=fzg0hFMgnC3qh7fah5k7mChdf9JARWezk49Z/MJhcHh5/KFPg+ZkILMnvKO7vZnrOxxhYNMExZNNtEj1NCgHRhXYauoPVLLp+NBJ4UNDKjCDFXGBKEop7D/hmkToNpiXxYjhHUpYSs5LsUUnDwPTfVrSO8SU4SdNaHJ2EAuED0s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758037954; c=relaxed/simple; bh=+hXZvqi6LNV3jJvzoftmaJUhD4I8rnkbyKCrYu8qGX8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cdagNDuFCWgJkqRKPlhyyX9JU8vd8pA9taFsQT+FNUNNheWiOX42g7e16qxKIf7okYJ6wmlU01Vdp/eWyfOXlBDH9du7+2ILpp0pO0Lu65Ok6EGG1Kec+ailQ1Gw1n5tdXsOGFDbJLPxH1UkYdsRhPldhpSmNt8RO3enq5Z6s7w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Ks1VWwLT; arc=none smtp.client-ip=95.215.58.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Ks1VWwLT" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1758037950; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tcyDoKI1I55gsyGOWBcccb0vzEVYkAWuqickrooeuto=; b=Ks1VWwLTmQl0VSHtcF+dQuTb7BBa5syPrziW5LqwZXTN8hWDwGBEjIwhpMvR0xlMVYezI5 5wUY6MvfkyTNra+DNK9hKUFulOnOV+9mk3KBejfinm9IHd9Ci8H8+ktxUXSHFogszgl+b5 vREnEV2mQsni9uk3N32Rdfhl8QQe1m8= From: Leon Hwang To: bpf@vger.kernel.org Cc: ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, yatsenko@meta.com, puranjay@kernel.org, davidzalman.101@gmail.com, cheick.traore@foss.st.com, chen.dylane@linux.dev, mika.westerberg@linux.intel.com, ameryhung@gmail.com, menglong8.dong@gmail.com, leon.hwang@linux.dev, kernel-patches-bot@fb.com Subject: [PATCH bpf-next v2 1/3] bpf: Allow union argument in trampoline based programs Date: Tue, 16 Sep 2025 23:52:09 +0800 Message-ID: <20250916155211.61083-2-leon.hwang@linux.dev> In-Reply-To: <20250916155211.61083-1-leon.hwang@linux.dev> References: <20250916155211.61083-1-leon.hwang@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT Currently, functions with 'union' arguments cannot be traced with fentry/fexit: bpftrace -e 'fentry:release_pages { exit(); }' -v AST node count: 6 Attaching 1 probe... ERROR: Error loading BPF program for fentry_vmlinux_release_pages_1. Kernel error log: The function release_pages arg0 type UNION is unsupported. processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0 ERROR: Loading BPF object(s) failed. The type of the 'release_pages' argument is defined as: typedef union { struct page **pages; struct folio **folios; struct encoded_page **encoded_pages; } release_pages_arg __attribute__ ((__transparent_union__)); This patch relaxes the restriction by allowing function arguments of type 'union' to be traced in verifier. Signed-off-by: Leon Hwang --- include/linux/bpf.h | 3 +++ include/linux/btf.h | 5 +++++ kernel/bpf/btf.c | 8 +++++--- 3 files changed, 13 insertions(+), 3 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 41f776071ff51..010ecbb798c60 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1119,6 +1119,9 @@ struct bpf_prog_offload { /* The argument is signed. */ #define BTF_FMODEL_SIGNED_ARG BIT(1) +/* The argument is a union. */ +#define BTF_FMODEL_UNION_ARG BIT(2) + struct btf_func_model { u8 ret_size; u8 ret_flags; diff --git a/include/linux/btf.h b/include/linux/btf.h index 9eda6b113f9b4..255f8c6bd2438 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -404,6 +404,11 @@ static inline bool btf_type_is_struct(const struct btf_type *t) return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION; } +static inline bool __btf_type_is_union(const struct btf_type *t) +{ + return BTF_INFO_KIND(t->info) == BTF_KIND_UNION; +} + static inline bool __btf_type_is_struct(const struct btf_type *t) { return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT; diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 64739308902f7..2a85c51412bea 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6762,7 +6762,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, /* skip modifiers */ while (btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); - if (btf_type_is_small_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t)) + if (btf_type_is_small_int(t) || btf_is_any_enum(t) || btf_type_is_struct(t)) /* accessing a scalar */ return true; if (!btf_type_is_ptr(t)) { @@ -7334,7 +7334,7 @@ static int __get_type_size(struct btf *btf, u32 btf_id, if (btf_type_is_ptr(t)) /* kernel size of pointer. Not BPF's size of pointer*/ return sizeof(void *); - if (btf_type_is_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t)) + if (btf_type_is_int(t) || btf_is_any_enum(t) || btf_type_is_struct(t)) return t->size; return -EINVAL; } @@ -7347,6 +7347,8 @@ static u8 __get_type_fmodel_flags(const struct btf_type *t) flags |= BTF_FMODEL_STRUCT_ARG; if (btf_type_is_signed_int(t)) flags |= BTF_FMODEL_SIGNED_ARG; + if (__btf_type_is_union(t)) + flags |= BTF_FMODEL_UNION_ARG; return flags; } @@ -7384,7 +7386,7 @@ int btf_distill_func_proto(struct bpf_verifier_log *log, return -EINVAL; } ret = __get_type_size(btf, func->type, &t); - if (ret < 0 || __btf_type_is_struct(t)) { + if (ret < 0 || btf_type_is_struct(t)) { bpf_log(log, "The function %s return type %s is unsupported.\n", tname, btf_type_str(t)); -- 2.50.1